kolvos
Mechanical
- Jul 28, 2012
- 13
Hi,
We have a system that functions at ~10^-6 Torr. Two of the gaskets we use are an Indium wire of 1mm. One is 350mm in perimeter and one is 280mm.
Both wires are in a standard gland, and are tightened with 8 NC10-24 screws. Currently there's no torque specification for these screws, and I'm trying to define one.
I'm using A.Roth's book: Vacuum Technologies, p. 308 in order to try and determine the force needed to exert on the seal.
It gives two examples: 0.8mm dia. wire: 7 kg/cm, and 1.5mm dia. wire: 56 kg/cm.
I sort of extrapolated a 25 kg/cm requirement for the 1mm dia. wire I'm using.
Next I tried calculating the torque needed for each screw, and got ~9.2 in-lbf.
This seems a rather small value, since most general torque charts I found stated around 25-30 in-lbf. Therefore, I'm a little worried give the 9.2 in-lbf. spec for our system.
What do you think? What happens I theoretically I specify a 25 in-lbf torque and I exert a force far greater than the theoretical calculated?
Thanks
We have a system that functions at ~10^-6 Torr. Two of the gaskets we use are an Indium wire of 1mm. One is 350mm in perimeter and one is 280mm.
Both wires are in a standard gland, and are tightened with 8 NC10-24 screws. Currently there's no torque specification for these screws, and I'm trying to define one.
I'm using A.Roth's book: Vacuum Technologies, p. 308 in order to try and determine the force needed to exert on the seal.
It gives two examples: 0.8mm dia. wire: 7 kg/cm, and 1.5mm dia. wire: 56 kg/cm.
I sort of extrapolated a 25 kg/cm requirement for the 1mm dia. wire I'm using.
Next I tried calculating the torque needed for each screw, and got ~9.2 in-lbf.
This seems a rather small value, since most general torque charts I found stated around 25-30 in-lbf. Therefore, I'm a little worried give the 9.2 in-lbf. spec for our system.
What do you think? What happens I theoretically I specify a 25 in-lbf torque and I exert a force far greater than the theoretical calculated?
Thanks
